M27 in many bands :)

[riklaunim]

This is my two-night imaging project of the M27 Dumbbell Nebula in H-alpha/[N-II], O-III, He-II and Ar-III. Imaging of this nebula isn't hard, although emission from Ar and He is quite low (close to S-II signal level). You can read more about those exotic bands here.

I've used C11, HEQ5 Pro Synscan, QHY5 (guider) + Celestron Radial Guider (OAG), DSI III Pro (bin2), f/6.3 reducer extended to f/5.6 - 5.9. Each channel 10 x 300 sec, H-alpha also extra 3 x 900 sec. Processed in Nebulosity (+ dark + flat). Raw stacks are here.

He-II will show areas of highest ionisation – closes to the white dwarf. 630 nm [O I] band (which I don't have) would show areas of neutral gas (outside ionised H-beta and O-III emission areas). For Ar-III I used weaker 775 nm band instead of the primary at 713nm – no matching filter. The same for quite strong Ne-III – no filter

H-a,O-III,O-III in different versions:

H-a,O-III,He-II:

H-a,He-II,He-II - He-II emission (blue) shown on the H-alpha/[N-II] red background:

[riklaunim]

O-III, Ar-III, He-II Channels:

H-alpha/[N-II]: 10 x 300; 10 x 300 + 3 x 900; and very stretched version to show a bit of the outer shell:

12nm H-alpha filter will pass also [N-II] doublet, that is around H-alpha band.

Bahtinov in action:

Seting up OAG camera to focus with the primary camera...:

And a single 300 sec H-alpha frame (CCD temp: 25,5C):

[riklaunim]

Found some other helium images here. I got quite similar results. Wonder how good those exotic bands will be on Saturn Nebula later this year. That nebula has much stronger singals and glows in many bands.